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224 one time than another; and this is so generally observed in London, and its connection with changes of weather so obvious, that many consider an increase of stench from drains to be a sure premonition of rain.

Some imagine, from the frequent occurrence of stench from sewers and drains, during easterly winds, that currents of air from that direction enter the drains, and force the stench back into the houses. But we know, that electrical movements are much more powerful than usual during easterly wind, and previous to and during rain, and consequently the more abundant extrication of gases and effluvia under such circumstances, may more properly be looked upon as an evidence of the chemical effects of electricity.

It has been noticed by many of our army medical officers at Gibraltar, that it is extremely difficult to keep armour clean during the north-east winds, which they call the black Levanters. These winds are certainly said to be moist, and this may probably be considered sufficient to account for their oxidating effects; but in order to ascertain that such processes of oxidation are affected by some less manifest influence, we have made comparative observations as to the time required, to oxidate or rust bright but unpolished plates of iron. When these plates are slightly sponged over with distilled